Problem: $-5stu - 7t - 2u + 5 = 9t + 4u - 10$ Solve for $s$.
Explanation: Combine constant terms on the right. $-5stu - 7t - 2u + {5} = 9t + 4u - {10}$ $-5stu - 7t - 2u = 9t + 4u - {15}$ Combine $u$ terms on the right. $-5stu - 7t - {2u} = 9t + {4u} - 15$ $-5stu - 7t = 9t + {6u} - 15$ Combine $t$ terms on the right. $-5stu - {7t} = {9t} + 6u - 15$ $-5stu = {16t} + 6u - 15$ Isolate $s$ $-{5}s{tu} = 16t + 6u - 15$ $s = \dfrac{ 16t + 6u - 15 }{ -{5tu} }$ Swap the signs so the denominator isn't negative. $s = \dfrac{ -{16}t - {6}u + {15} }{ {5tu} }$